1. Field of the Invention
The present invention relates to a recording/reproducing apparatus, a recording/reproducing method, and an information recording medium. In particular, the present invention relates to a recording/reproducing apparatus, a recording/reproducing method, and an information recording medium which enable an optimum recording laser output value to be obtained.
2. Description of the Related Art
In an apparatus for optically recording/reproducing information, the sizes of marks to be formed on an information recording medium are varied depending upon the intensity of a recording laser output. Thus, in order to secure compatibility between media and to record data with accuracy, it is required to appropriately set a recording laser output value. When a recording laser output is not sufficient, the sizes of marks become smaller. In this case, the amplitude of a reproduced signal becomes smaller, making it impossible to correctly reproduce data. In contrast, when an excess recording laser output is given, the sizes of marks become larger. Therefore, a signal is written not only on a track on which data is to be written but also on an adjacent track, i.e., crosserase occurs.
In the case where crosserase occurs, when data is written on a track B adjacent to a track A, data on the track A is overwritten with the data on the track B. This causes the quality of a reproduced signal from the track A to degrade, resulting in that a correct reproduced signal cannot be obtained from the track A.
In general, there is variation in characteristics in an information recording medium. Moreover, the surrounding environment varies. Therefore, a recording laser output value is not constant. In order to overcome this problem, in a conventional apparatus for optically recording/reproducing information, test data is recorded in and reproduced from a test region in an information recording medium prior to writing data, and the amplitude of a reproduced signal from the test region is checked, whereby an optimum recording laser output is set.
However, in the conventional apparatus, test data is recorded in and reproduced from an identical track. Therefore, it is impossible to accurately estimate an influence of a recording laser output on an adjacent track when an excess recording laser output is given. Thus, the conventional apparatus cannot prevent the quality of a signal from degrading due to crosserase. Furthermore, in recent years, high-density recording has been demanded for the purpose of increasing the capacity of an information recording medium. This requires tracks of the information recording medium to be narrower. Accordingly, it will become more important to overcome the problem of the degradation of a signal quality due to crosserase.